Red cell fragments are formed when fibrin strands come in contact with circulating red cells. The strands cut a small piece from the original cell. Several descriptive names have been used for fragmented red cells, depending on the resulting shape of the fragment. These include pre-keratocyte (blister cell), keratocyte (horn cell or helmet cell), and schistocyte (more of a catch-all term).

Schistocytes can be seen in disseminated intravascular coagulation (DIC), micropathic hemolytic anemia, glomerulonephritis, and hemolytic anemia resulting from mechanical trauma to the red blood cells (such as severe burns).